Better get your eyes checked, it says "Tap", in that wonderfully crappy 5x7 font with no descenders, because they were too cheap to get a display module with an eighth row of pixels. That lowercase "g" bothers me more. I could accept this back in the 1980s, but it's total bullshit now.

Hot desking is where you don't have an assigned desk when you get to work, but rather take whatever desk is available. The button on the phone is to log in so the system knows what physical phone corresponds to your extension.